What is the formula used to estimate drip edge for a hip roof?

The formula for estimating the drip edge for a hip roof is based on calculating the total perimeter of the roof that requires protection with drip edge. In this case, the correct formulation involves adding twice the length (L) for both the sides of the hip roof and twice the width (W) for its ends.

This approach works because a hip roof has four sides, and you want to ensure that the drip edge is applied along the entire perimeter where the roof meets the eave. By summing both lengths and widths—specifically, L + L + W + W—you derive the total distance that the drip edge will need to cover. This total perimeter provides the necessary measurement to estimate the length of drip edge required for installation effectively.

The incorrect options generally do not adequately represent the geometry of a hip roof or fail to contribute to a comprehensive assessment of how the perimeter is formed. This understanding is essential for ensuring proper drainage and preventing water leakage under the roof covering, thereby protecting the structure.